Suds-controlling composition for aqueous compositions

ABSTRACT

A suds-controlling composition of improved stability in aqueous surfactants, such as detergents, is disclosed comprising a silicon antifoam consisting essentially of a liquid branched polyorganosiloxane and a finely divided filler having a hydrophobic surface; a polyorganosiloxane polyoxyalkylene copolymer; and a cyclic organopolysiloxane. The silicone antifoam and polyorganosiloxane polyoxyalkylene copolymer are combined in a ratio of 1/3 to 3/1.

This is a continuation of application(s) Ser. No. 07/994,393 filed onDec. 21, 1992 now abandoned.

This invention relates to suds controlling compositions which are usefulin aqueous surfactant compositions. They particularly relate tocompositions comprising silicone anti-foams which show an improvedstability in said aqueous surfactant compositions, particularly liquiddetergent compositions.

Aqueous surfactant compositions are used in a variety of applications.Such applications include hard surface cleaners, textile scouringcompositions, carpet cleaners, general industrial and domestic cleaningcompositions, laundry detergent compositions and cleaning and waxingcompositions. In many of these applications it is desired to control theamount of foam generated, for example during the washing action infront-loading washing machines, or in the rinsing stage of a textilelaundry operation or a floor cleaning operation. A number of antifoam orfoam control compounds have been developed and suggested for use in suchaqueous surfactant compositions. One particularly useful type ofantifoams or foam control compounds is based on silicone polymers,preferably in the presence of silica particles. The present invention isespecially concerned with providing a suds controlling composition whichwill be supplied in an aqueous surfactant composition, as opposed tothose which are supplied as a powder composition, intended for eventualuse in an aqueous medium.

British patent application 1 544 736 describes a concentrated,essentially homogeneous, low-sudsing liquid detergent compositioncomprising apart from nonionic and anionic surfactants an effectiveamount, preferably from 0.01% to 5% by weight based on the total weightof the composition of a self-emulsifiable suds-controlling agent,comprising a silicone suds controlling agent and an emulsifier for thesilicone suds-controlling agent. The preferred emulsifiers used in theself-emulsifiable suds-controlling agent are said to be typicallyrepresented by the formula R_(a) SiY_(4-a), wherein a is from 0 to 3, Ris a C₁₋₃₀ alkyl or a group of the formula --R'--(OR')_(b) OR", whereinR' is alkylene, b is from 1 to 100 and R" is a capping group, and Y is agroup of the formula [--OSi(R)₂ --]_(c) --OSiR₃, wherein R is as aboveand c has a value of from 1 to 200, at least one R group in the compoundhaving the formula --R'--(OR')_(b) OR". The silicone suds-controllingagent are described as siloxanes having the general structure--[SiO(RR²)--]_(x) -- wherein x is from 20 to 200 and R and R² are eachalkyl or aryl, either singly or in combination with various solidmaterials such as silica aerogels and xerogels and hydrophobic silicasof various types. Another type of suds-controlling agent comprises asilicone fluid, a silicone resin and silica. Silicone resins aredescribed as 3-dimensional polymers arising from the hydrolysis of alkyltrichlorosilanes. Such suds-controlling agents have been described inU.S. Pat No. 3,455,839. The silicone resin materials used, are intendedto react with the silanol groups of the silica, in order to render itssurface hydrophobic.

We have found that when such suds-controlling agents are added toaqueous surfactant compositions, especially of an unbuilt andunstructured type, the compositions, though efficient in the controllingof foam when initially mixed with the suds-controlling agent, very oftendo not retain their efficiency in controlling the foam for asufficiently long time to enable long term storage. This is not becausethe suds-controlling agent loses its intrinsic efficiency, but becausethe suds-controlling agents are not stable in the surfactantcomposition, and are thus not evenly dispersed throughout saidcomposition. This is often due to either coalescence of thesuds-controlling agent droplets, which were dispersed in the aqueoussurfactant composition, or to phase separation resulting in eithercreaming of sedimentation. Coalescence is usually caused by preferentialsolubility of the emulsifiers, resulting in the dispersed particleslosing the stabilising presence of emulsifiers at the interface betweenthe suds-controlling agent and the surfactant solution. The latter findsits cause often in the differing specific gravities of the internal andexternal phases. By not having correct gravity adjustment of thesuds-controlling agent, in order to match as closely as possible thespecific gravity of the liquid surfactant compositions, the separationproblem becomes worse.

Stabilising of compounds in liquid detergent compositions by differentmeans is also known. For example E.P. specification 81 908 describeslow-foaming detergent compositions consisting of a micellar structuredliquid and a liquid polysiloxane antifoaming agent. Stabilisation occursby keeping components in homogeneous suspension by the structure of themicellar system. The preferred compositions contain 6 to 15% by weightof a mixture of anionic sulfonate or sulfate detergents, alkali metalsoaps of C₁₂₋₁₈ fatty acid, and nonionic detergents and preferably18-35% by weight of a solid detergency builder (e.g. Natripolyphosphate). The low-foaming detergent composition has anon-Newtonian structure. E.P. 126 500 describes similar detergentcompositions which are micellar structured liquids. However, there is aneed to find different stabilisation methods, especially fornon-structured and non-built liquid surfactant compositions.

Nothing in the prior art indicates how best such improvement instability would be obtained. There is particularly no mention that theuse of special branched polyorganosiloxane materials in the antifoaminstead of linear organosiloxane polymers might improve the stability inliquid surfactant compositions, especially of the unbuilt andunstructured type.

We have now surprisingly found that if the suds-controlling compositioncomprises a mixture of certain polyoxyalkylene polysiloxane copolymersand a silicone antifoam which consists of a branched siloxane and solidparticles, a much more stable system is provided when mixed with anaqueous surfactant composition.

According to a first aspect of the invention there is provided, asuds-controlling composition which is liquid at 25° C., comprising

(a) 100 parts by weight of a silicone antifoam which consistsessentially of (i) a liquid branched polyorganosiloxane material,wherein at least 50% of all units present have the general formula R₂--Si--O_(2/2), wherein R denotes a monovalent hydrocarbon group havingup to 24 carbon atoms and wherein at least 2 units have the generalstructure R--Si--O_(3/2) or Si--O_(4/2), any other units having thegeneral formula ##STR1## wherein a has a value of from 0 to 3 and R'denotes a group R or a hydrogen or hydroxyl group, and (ii) a finelydivided filler having its surface rendered hydrophobic, and

(b) from 33 to 300 parts by weight of a polyorganosiloxanepolyoxyalkylene copolymer, which is neither fully soluble in an aqueoussurfactant solution nor fully soluble in the liquid polyorganosiloxane(a)(i).

Silicone antifoams which are useful as part (a) of the suds-controllingcomposition of the invention, are known in the art, and have beendescribed in a number of publications.

G.B. 639 673 describes an antifoam composition comprising an intimatemixture of a silica aerogel and a viscous but flowable methyl siloxanepolymer containing an average of from 1.75 to 2 carbon atoms per atom ofsilicon and having semi-rubbery characteristics. It is stated that themethyl siloxane polymer retains its ability to flow at roomtemperatures. Several methods of manufacturing the methyl polysiloxaneare described, including partial oxidation of non-rubbery liquid methylsiloxane polymers, cohydrolysis and condensation of hydrolysable mono-and dimethyl silanes or polymerisation of non-rubbery liquid methylsiloxane in the presence of an acid or alkali catalyst. It is clear fromthis that branched polysiloxane materials are obtained.

E.P. 31 532 describes an antifoam composition which is prepared bymixing a liquid polydimethylsiloxane and a lightly crosslinkedpolysiloxane resin with a molecular weight of from 1000 to 10000 andhaving 0.1 to 10% by weight of hydroxyl groups, and heating it up with acatalyst and optionally a solvent till the viscosity is at least 200mPa.s at 20° C., followed by mixing and heating the resultant compoundwith silica aerogel which has been silanised. The siliconeblock-polymers thus obtained are stated to give improved storagestability in powder detergents.

E.P. 217 501 describes improved foam control compositions which comprisea liquid siloxane component and a finely divided filler having itssurface rendered hydrophobic. The liquid siloxane component has acertain minimum viscosity and is obtained by mixing and reactingpolydiorganosiloxanes having triorganosiloxy end groups,polydiorganosiloxanes having at least one terminal silanol group and anorganopolysiloxane resin comprising monofunctional and tetrafunctionalsiloxanes units and at least one silanol group.

E.P. 273 448 describes a foam suppressing composition which is producedthrough free-radical polymerisation of mixtures ofpolydiorganosiloxanes, silica and free radical polymerisationinitiators. Some of the compositions described add pendant vinylmodified silicone oil, which would result in a branched siloxane fluid.

German patent application DE 38 05 661 describes a method of makingimproved foam control agents by oxidation of linearpolydimethylsiloxanes in oxygen at high temperatures in the presence ofan organic peroxide, followed by mixing in silica particles and thefurther reaction with a low molecular weight silane or silazane.

Our copending application G.B. 9115590.3 describes a method for making abranched organopolysiloxane antifoam component which comprises bringingabout a hydrosilylation reaction between a vinyl end-blockedpolydiorganosiloxane and a volatile low viscosity organohydrosiloxane inthe presence of a noble metal catalyst.

Although silicone antifoams which are useful as part (a) of thesuds-controlling compositions of the invention are known, there is noindication in any of the prior art that they would be particularlyuseful in aqueous surfactant compositions. There is in particular noindication that they would give improved stability in liquid detergentcompositions, especially those which are unbuilt and unstructured, whencombined with certain polyoxyalkylene polyorganosiloxane copolymers.

The nature of the liquid branched polyorganosiloxane material is notcritical, provided at least 50% of all units present have the formula R₂SiO_(2/2) and at least two units have either the formula RSiO_(3/2) orthe formula SiO_(4/2). Preferably at least 80% of all units have theformula R₂ SiO_(2/2), most preferably at least 90%. It is preferred thatall other units are either units of the formula RSiO_(3/2) or SiO_(4/2).These other units may be present as individual units in the siloxanechains, or they may be present as little clusters, from which a numberof siloxane chains extend. Thus a very loose network is formed ofpolyorganosiloxane chains giving a fluid material. Each group R presentin the branched polyorganosiloxane material may be an aliphatic oraromatic hydrocarbon group having up to 24 carbon atoms, preferably upto 18 carbon atoms. Suitable groups include alkyl, aryl, alkaryl,aralkyl, alkenyl or alkynyl groups, for example methyl, ethyl, dodecyl,octadecyl, phenyl, vinyl, phenylethyl or propargyl. Preferably at least60% of all R groups are methyl or phenyl groups, more preferably atleast 80%. It is most preferred that substantially all R groups aremethyl or phenyl groups, especially methyl groups. Units of the generalformula ##STR2## wherein a has a value of from 0 to 3 and R' denotes agroup R or a hydrogen or hydroxyl group, may also be present, but theyare preferably kept to a minimum. The presence of R' groups which aredifferent from R, would generally only occur where the branchedpolyorganosiloxane material is prepared using organosilicon compoundswhich have silicon-bonded R' groups present. Suitable branched siloxanepolymers may be made according to any one of the methods described inthe patent applications G.B. 639 673, E.P. 31 532, E.P. 217 501, E.P.273 448 or DE 38 05 661, which are hereby included by reference.

The finely divided filler (ii) which is used in combination with thebranched polyorganosiloxane (i) in order to form the silicone antifoam(a) may be any one of the well known filler materials used in the art.Suitable fillers are described in a number of patent specifications andinclude TiO₂, Al₂ O₃, aluminosilicates and SiO₂ with a surface area asmeasured by BET measurement of at least 50 m² /g. Preferred fillers aresilica fillers which can be made according to any of the standardmanufacturing techniques for example thermal decomposition of a siliconhalide, decomposition and precipitation of a metal salt of silicic acid,e.g. sodium silicate and a gel formation method. Suitable silicas foruse in an antifoam include therefore fumed silica, precipitated silicaand gel formation silica. The average particle size of these fillers maybe such that the diameter ranges form 0.1 to 20 μ, preferably from 0.5to 5 μ, most preferably 1 to 2.5 μ.

The surface of the filler particles is rendered hydrophobic in order tomake the antifoam more efficient in aqueous systems. Rendering thefiller particles hydrophobic may be done either prior to or afterdispersing the filler particles in the liquid polyorganosiloxanecomponent. This can be effected by pretreatment of the filler particleswith fatty acids, reactive silanes or reactive siloxanes. Examples ofsuitable hydrophobing agents include stearic acid,dimethyldichlorosilane, trimethylchlorosilane, hexamethyldisilazane,hydroxyl end-blocked or methyl end-blocked polydimethylsiloxanes,siloxane resins or mixtures of two or more of these. Other hydrophobingagents may also be used, but the above exemplified materials are themost effective. Fillers which have already been treated with suchcompounds are commercially available from a number of sources.Alternatively, the surface of the filler may be rendered hydrophobic insitu, i.e. after the filler has been dispersed in the liquidpolyorganosiloxane material. This may he effected by adding to theliquid polyorganosiloxane component prior to, during or after thedispersion of the filler, an appropriate amount of a hydrophobing agentof the kind described above as reactive silanes or siloxanes, andheating the mixture sufficiently to cause reaction, e.g. a temperatureof at least 40° C. It is even possible to add the fillers and thehydrophobing agent to the ingredients used to make the liquid branchedpolyorganosiloxane material, and make said polyorganosiloxane at thesame time as render the surface of the filler hydrophobic.

The quantity of hydrophobing agent to be employed will depend forexample on the nature of the agent and of the filler, and will beevident or ascertainable by those skilled in the art. Sufficienthydrophobic agent should be employed to endow the filler with at least adiscernible degree of hydrophobicity. The amount of filler used is notcritical and may be in the range of form 2 to 20% by weight of the totalantifoam. Preferably form 3 to 15% is used.

The silicone antifoam compound (a) which is useful in a suds controllingcomposition according to the invention is preferably a flowablecompound, even though the viscosity may be very high, bordering on theelastomeric. It is particularly preferred that the silicone antifoam hasa viscosity at 25° C. of from 500 to 50,000 mPa.s, more preferably from1,000 to 40.000, especially 3,000 to 35,000 mPa.s. Most preferably asuitable silicone antifoam will have a viscosity of from about 5,000 to30,000 mPa.s. This viscosity will result from a number of factors,including starting with the appropriate polyorganosiloxane material (i),adding the appropriate amount of filler (ii) and using a sufficientamount of shear to mix the two components together. It will be clear toa person skilled in the art how these factors can be used to obtain asilicone antifoam of the desired viscosity.

The second essential ingredient of the suds controlling compositionaccording to the invention is a polyorganosiloxane polyoxyalkylenecopolymer (b). This copolymer serves as a kind of dispersing aid for thesilicone antifoam and as an emulsifier for the silicone antifoam whendispersed in an aqueous surfactant composition, e.g. liquid detergentcomposition.

Suitable copolymers have been described in a number of publications andare generally well known in the art. Suitable polyorganosiloxanepolyoxyalkylene copolymers have a number of units X of the generalformula ##EQU1## and at least one unit Y of the general formula ##EQU2##R' denotes a monovalent hydrocarbon group having up to 24 carbon atoms,a hydrogen atom or a hydroxyl group, preferably R as previouslydescribed, including preferred values for R and a has a value of 0, 1, 2or 3. R denotes a hydrocarbon group having up to 24 carbon atoms,preferably those values as denoted above as preferred values for R. R"denotes a groups of the general formula A--(OZ)_(c) --B, wherein 2 is adivalent alkylene unit having from 2 to 8 carbon atoms, A denotes adivalent hydrocarbon radical having from 2 to 6 carbon atoms, optionallyinterrupted by oxygen, B denotes a capping unit and c is an integer witha value of from 3 to 30. it is preferred that A is a divalent alkyleneunit, preferably having 2 to 4 carbon atoms, e.g. dimethylene, propyleneor isobutylene. Z is preferably a divalent alkylene unit having 2 or 3units, e.g. dimethylene or isopropylene. B may be any of the knownend-capping units of polyoxyalkylene groups, e.g. hydroxyl, alkoxy,aryloxy, acyl, sulfate, phosphate or mixtures thereof, most preferablyhydroxyl, alkoxy or acyl.

Units X and Y may be the majority of units in the copolymer, butpreferably they are the only units present in the copolymer. They may belinked to each other in a way to form random copolymers or blockcopolymers. The units Y may be distributed along the siloxane chain ofthe copolymer or they may be placed at one or both ends of such siloxanechain. Suitable copolymers will therefore have one of the followingstructures, wherein X' denotes one or more units X and Y' denotes one ormore units Y: X'Y', Y'X'Y', X'Y'X', Y'(X'Y')_(e), Y'(X'Y')_(e) X',X'(Y'X')_(e) or any one of the above structure wherein one or more Y'groups have divalent polyoxylakylene units which are linked at eitherend to a siloxane unit, thus forming a type of crosslinkedpolyorganosiloxane polyoxyalkylene unit. The value of e is notimportant, provided the copolymer satisfies the conditions of solubilitylaid down. Suitable copolymers have been described for example in PatentSpecifications G.B. 1 023 209, G.B. 1 554 736, G.B. 2 113 236, G.B. 2119 394, G.B. 2 166 750, G.B. 2 173 510, G.B. 2 175 000, E.P. 125 779,E.P. 212 787, E.P. 298 402 and E.P. 381 318.

It is preferred that the polyorganosiloxane polyoxyalkylene copolymerhas a substantially linear siloxane backbone, i.e. that the value of ais 2 and b is 1 for the majority of units present in the copolymer. Thiswill result in a so-called ABA type polymer or in a rake type polymer.In the former units Y will be situated at each end of the siloxanechain, while in the latter units X and Y are dispersed along thesiloxane chain, with the oxyalkylene units pending from the chain atcertain intervals. More preferred are those copolymers which have thegeneral formula ##STR3##

R in these more preferred copolymers may denote any alkyl or aryl grouphaving up to 18 carbon atoms, more preferably 6. Particularly preferredare methyl, ethyl or phenyl groups. Especially preferred are thosecopolymers wherein at least 80% of all R groups in the copolymer, mostpreferably substantially all R groups are methyl groups. A in these morepreferred copolymers denotes a C₂ or C₃ alkylene unit, most preferablypropylene or isopropylene. Z preferably denotes a dimethylene group forthe majority of Z groups present in the copolymer. More preferably atleast 70% of all Z groups are dimethylene groups, most preferably all Zgroups, making the polyoxyalkylene portion a polyoxyethylene portion. Bpreferably denotes a hydroxyl group or an acetyl group. The values of x,y and c are chosen thus that the copolymer is not fully soluble in anaqueous surfactant solution or not fully soluble in the liquidpolyorganosiloxane material. It is therefore preferred to balance thehydrophobic nature of the copolymer, which is determined to a largeextent by the value of x, with the hydrophilic nature, which isdetermined to a large extent by the value of y and c. E.g. if the valueof x is large, a long siloxane chain is formed, which will encouragesolubility of the copolymer in the organopolysiloxane material (i). Thismay be balanced by increasing the amount of units having oxyalkylenegroups (value of y) and by the size of the polyoxyalkylene groups (valueof c, especially where Z is dimethylene).

For best stability results, polyorganosiloxane polyoxyalkylenecopolymers are to be selected according to the surfactant composition.This may be influenced by the alkalinity of the composition, thehydrophilic/lipophilic balance etc. For a majority of aqueous surfactantcompositions, particularly preferred polyorganosiloxane polyoxyalkylenecopolymers will be those where the value of x+y is in the range of from50 to 500, more preferably 80 to 350. The preferred ratio of y/x+y isfrom 0.02 to 0.1, more preferably 0.05 to 0.08. The value of c ispreferably in the range from 4 to 40, more preferably 5 to 20, mostpreferably 7 to 15. A particularly useful copolymer is the one whereinx+y has a value of about 100, y/x+y has a value of about 0.06 and c hasa value of 12, provided all Z units are dimethylene units.

Where higher molecular weight polyorganosiloxane polyoxyalkylenecopolymers are preferred, e.g. those which are solid, it is preferred tomix these copolymers with a diluent, e.g. a linear or cyclicpolydiorganosiloxane polymer of very low viscosity. Such polymers areknown and are described in more detail under optional ingredients below.

Polyorganosiloxane polyoxyalkylene copolymers which are useful in sudscontrolling compositions according to the invention are known in theart, have been described in a number of patent specifications, asdescribed above, and many of them are commercially available. They maybe made by a variety of methods, which have also been described orreferenced in the above mentioned specifications, which are herebyincluded by reference. One particularly useful way of making suitablecopolymers is by reaction of polyorganosiloxanes having silicon-bondedhydrogen atoms with appropriate allylglycols (allyl-polyoxyalkylenepolymers) in the presence of a noble metal catalyst. A hydrosilylationreaction will ensure the addition reaction of the allyl group to thesilicon atom to which the hydrogen atom was bonded.

The suds-controlling composition comprises at least 33 parts by weightof the polyorganosiloxane polyoxyalkylene copolymer (b) for every 100parts by weight of the silicone antifoam (a) and at most 300 parts (b)per 100 parts of (a). Preferably there are at least 35 to 150 parts ofcopolymer (b) for every 100 parts of antifoam (a), most preferably from100 to 120 parts of (b) for every 100 parts of (a). The components (a)and (b) may be mixed together in any known way, but are preferably mixedtogether using a reasonable amount of shear, so as to ensure a properdispersion of the antifoam in the copolymer. This will also encourage aproper dispersion when the suds-controlling composition is mixed into adetergent composition.

Apart from the two essential ingredients, a suds-controlling compositionaccording to the present invention may also include certain amounts ofother components. Such additional optional ingredients may includeorganic foam controlling compounds, e.g. mineral oil, linearorganopolysiloxane fluids, e.g. polydimethylsiloxane materials and alkylmethyl silicone, organic polymers soluble in silicone e.g.polyisobutene, polyisopentene, cyclic organopolysiloxane fluids, e.g.cyclic dimethyltetrasiloxane and cyclic dimethylpentasiloxane,preservatives, pH stabilisers and extra hydrophilic or hydrophobicfiller materials e.g., clays, quartz. The amount of these materials maybe quite high, and especially where the linear or cyclicorganopolysiloxanes are concerned, as much as 200 to 400 parts by weightmay be added to the composition e.g. 50% by weight of totalsuds-controlling composition. The addition of these ingredients may beused to adjust the specific gravity of the suds-controlling composition,so that it matches that of the aqueous surfactant composition, e.g. thedetergent composition.

The suds-controlling composition according to the present invention isparticularly useful in controlling foam of aqueous surfactantcompositions, more particularly of liquid detergent compositions. It isparticularly useful in those detergent compositions which have a strongtendency to foaming, for example hard surface cleaners and liquidlaundry detergent compositions. The latter are of particular interest,as there has been a search for a stable and efficient suds-controllingagent in such compositions, particularly where unbuilt and unstructureddetergent compositions are concerned.

According to the invention there is provided in another aspect anaqueous surfactant composition, e.g. a liquid detergent compositioncomprising

(A) from 10 to 50 parts by weight of a nonionic surfactant,

(B) from 10 to 50 parts by weight of an anionic surfactant,

(C) sufficient of a suds-controlling composition comprising

(a) 100 parts by weight of a silicone antifoam which consistsessentially of (i) a liquid branched polyorganosiloxane material whereinat least 50% of all units present have the general formula R₂--Si--O_(2/2), wherein R denotes a monovalent hydrocarbon group havingup to 15 carbon atoms and wherein at least 2 units have the generalstructure R--Si--O_(3/2) or Si--O_(4/2), any other units having thegeneral formula R'_(a) --Si--O_(4-a/2) wherein a has a value of from 0to 3 and R' denotes a group R or a hydrogen or hydroxyl group, and (ii)a finely divided filler having its surface rendered hydrophobic, and

(b) from 33 to 300 parts by weight of a polyorganosiloxanepolyoxyalkylene copolymer, which is liquid at ambient temperature, andwhich is neither fully soluble in the surfactant composition nor fullysoluble in the liquid polyorganosiloxane (a)(i)

to give a silicone antifoam content of from 0.01 to 5% by weight basedon the total weight of the liquid detergent composition.

Aqueous surfactant composition are well known, and have been describedin a number of patent specifications. Examples of such specificationsinclude G.B. 1 554 736, G.B. 2 078 246, G.B. 2 132 629, G.B. 2 151 252,G.B. 2 158 453, E.P. 205 088, E.P. 221 774, E.P. 328 182, E.P. 346 111,U.S. Pat. No. 4,110,262, U.S. Pat. No. 4,147,649 U.S. Pat. No. 4,798,679U.S. Pat. No. 4,992,196 and U.S. Pat. No. 5,035,832, which are herebyincluded by reference. They may be built or unbuilt, structured orunstructured. Preferred aqueous surfactant compositions according to theinvention are unbuilt and unstructured compositions.

Most preferred are liquid detergent compositions. Typically a liquiddetergent composition comprises a nonionic surfactant, for examplecondensation products of alkylene oxide with organic hydrophobiccompounds, e.g. condensation products of ethylene oxides and alkylphenols, condensation products of aliphatic alcohols and ethylene oxide,condensation products of ethylene oxide and propylene oxide, thecondensation product of ethylene oxide and the product of reaction ofpropylene oxide and ethylene diamine, preferably the condensationproducts of poly (1-20) oxyethylene and primary and secondary C₉₋₁₈alcohols. A typical aqueous surfactant composition also comprisesanionic surfactants, e.g. alkyl benzyl sulfonates, alkyl glyceryl ethersulfonates, alkyl ether sulfates and sulfonated fatty acids. Othersurfactants may also be included, e.g. semi-polar, ampholytic andzwitterionic surfactants, such as water soluble amine or phosphineoxides containing an alkyl moiety and optionally a hydroxyalkyl moiety,aliphatic derivatives of heterocyclic secondary and tertiary amines andderivatives of aliphatic quaternary ammonium, sulfonium and phosphoniumcompounds.

Other optional ingredients of aqueous surfactant compositions includealkanolamines, fatty acid corrosion inhibitors, alkali metal bases,solvents, especially alcohol-water mixtures, electrolyte salts, opticalbrighteners, enzymes, bleaching agents, colorants and anti-microbialagents. These compounds are all well known to the person skilled in theart.

The suds-controlling composition according to the invention may beintroduced into the aqueous surfactant composition by any acceptablemeans. This may vary from mere mixing of the ingredients to applyinghigh shear in order to establish a good dispersion of the sudscontrolling composition in the aqueous surfactant composition. Bettershear will result in smaller particle size of the suds-controllingcompositions, and hence in a better stability of the total surfactantcomposition. It is however important that the suds-controlling agent isprepared separately, including at least the two essential ingredients(silicone antifoam and polyorganosiloxane polyoxyalkylene copolymer),and added to the surfactant composition as a single ingredient.

There now follow a number of examples which illustrate the invention.All parts and percentages are by weight, unless otherwise stated.

PREPARATIONS Polyorganosiloxane Polyoxyalkylene Copolymer

74.05 * x parts of a mixture of octamethyltetracyclosiloxane anddecamethylpentasiloxane were heated up together with 60.05 * y parts ofa short polymer of the formula (CH₃)₃ SiO[(CH₃)SiH--O]_(n) --Si(CH₃)₃wherein a is on average 12 and 162-(162*y/40) parts of hexamethyldisiloxane to a temperature of 55° C. under a nitrogen blanket. 0.1% w/wof trifluoromethane sulphonic acid was carefully added together with afew drops of water. The mixture was stirred for 5 hours at 70° C., andafter cooling, neutralized with 0.5% w/w NaHCO₃. Filtration gave asiloxane of the general formula (CH₃)₃ --Si--O[(CH₃)₂ SiO]_(x)--[(CH₃)HSiO]_(y) --Si(CH₃)₃

The polymers were reacted with allyl polyethylene glycol of the formulaCH₂ ═CH--CH₂ --(OCH₂ CH₂)_(z) --OR in the presence of isopropanol and aplatinum containing catalyst at 70° C., till the reaction was complete,which was followed by infra red spectroscopy of the presence of SiHgroups. This was followed by removal of the volatile materials underreduced pressure.

The following copolymers were made:

    ______________________________________                                        x               y      z           R                                          ______________________________________                                        A       94          6       7        acyl                                     B       94          6       7        OH                                       C       94          6      12        acyl                                     D       94          6      12        OH                                       E      194          6      12        acyl                                     F      290          5       7        acyl                                     G      290          5      12        acyl                                     H      318          32     12        acyl                                     I      329          21     12        acyl                                     ______________________________________                                    

Silicone Antifoam

A silicone antifoam (I) was made according to EP 217,501, by adding to aglass flask, equipped with thermometer, stirrer, dropping funnel andinert gas supply, 61.1 parts of trimethylsiloxy end-blockedpolydimethylsiloxane having a viscosity at 25° C. of 10⁻³ m² /s, 30.5parts of a hydroxy end-blocked polydimethylsiloxane having on averageabout 900 Si atoms per molecule and 2.2 parts of a 70% solution inxylene of polysiloxane resin having (CH₃)₃ SiO_(1/2) units and SiO₂units in a ratio of from 0.5:1 to 1.2:1. The mixture was stirred at roomtemperature till it was will mixed and then heated to 115° C. undernitrogen. When the mixture reached that temperature, 0.87 parts ofpotassium silanolate were added and the temperature was held for afurther 30 minutes. Then the mixture was allowed to cool to 40° C. and0.046 part of glacial acetic acid was added and stirred to ensureneutralization. Thus a liquid siloxane component was obtained which hada viscosity of about 12×10⁻³ m² /s at 25° C. 95 parts of this siloxanewas mixed with 5 parts of hydrophobic silica to give a silicone antifoamhaving a viscosity of about 2×10⁻² m² /s at 25° C.

Two comparative silicone antifoams (CI and CII) were also made, in whichonly linear polydimethylsiloxane and hydrophobic silica was used, CI wasa higher density antifoam than CII.

Suds Controlling Composition

Suds-controlling compositions according to the invention were made bymixing either 20 parts of the antifoam (I) with 30 parts of apolyorganosiloxane polyoxyalkylene copolymer (A-I) or 25 parts of theantifoam (I) with 25 parts of a polyorganosiloxane polyoxyalkylenecopolymer (A-I). The mixing was achieved in a beaker by stirring with a4-bladed paddle stirrer for 1 hour. Where indicated below (as cyclics)50 parts of a mixture of octamethylcyclotetrasiloxane anddecamethylcyclopentasiloxane were added and stirred in for an extrahour. This gave the following suds-controlling compositions according tothe invention:

    ______________________________________                                               antifoam (I)                                                                             copolymer (type)                                                                           cyclics                                        ______________________________________                                        SCC1     25           25 (I)       --                                         SCC2     25           25 (C)       50                                         SCC2A    25           25 (C)       --                                         SCC3     25           25 (G)       50                                         SCC4     25           25 (E)       50                                         SCC5     25           25 (H)       50                                         SCC6     20           30 (G)       50                                         SCC7     20           30 (E)       50                                         SCC8     20           30 (C)       50                                         SCC9     20           30 (H)       50                                         SCC10    25           25 (I)       50                                         SCC11    20           30 (I)       50                                         SCC12    25           25 (A)       50                                         SCC13    25           25 (D)       50                                         SCC14    25           25 (B)       50                                         SCC15    20           30 (A)       50                                         SCC16    20           30 (B)       50                                         SCC17    25           20 (G) + 5 (H)                                                                             50                                         SCC18    25           15 (G) + 10 (H)                                                                            50                                         SCC19    25           10 (G) + 15 (H)                                                                            50                                         SCC20    25            5 (G) + 20 (H)                                                                            50                                         ______________________________________                                    

Comparative suds-controlling compositions were made by mixingcomparative antifoam (CI) with certain polyorganosiloxanepolyoxyalkylene copolymers as shown below.

    ______________________________________                                               antifoam (type)                                                                          copolymer (type)                                                                           cyclics                                        ______________________________________                                        SCC-C1   25 (CI)      25 (I)       --                                         SCC-C2   25 (CII)     25 (A)       50                                         SCC-C3   25 (CII)     25 (C)       50                                         ______________________________________                                    

Stability Testing

A liquid detergent composition was prepared, which consisted of 13%Nansa® SS60, 13% Empicol® KC7, 5% fatty acids, 5% oleic acid, 10%ethanol, 5% triethanolamine, 1.5% NaOH and the rest water. This wasmixed with a 4-bladed propeller and to 96 g of the detergent compositionwas added 4 g of either SCC1 or SCC2A, and the mixing was continued for15 minutes. For all other suds-controlling agent, 20 g of the SCC2 andSCC3-20 were added to 80 g of the liquid detergent compositions. Highlevels of addition were used to accelerate any instability which mayoccur. Therefore stability data given here are shorter than would beexpected when the suds-controlling composition would be added at normallevels. Comparative examples were made by mixing SCC-C2 and SCC-C3 asindicated above, and also by mixing SCC-C1 to a commercially availablehigh density liquid detergent composition.

All samples were tested for stability, and none of the examplesaccording to the invention have shown signs of major coalescence of thesuds-controlling composition particles. Some samples have been aged for5 months and still do not show signs of coalescence. The threecomparative examples however, showed major signs of instability, with inthe case of SCC-C1, the silicone antifoam separating out within 1minute, the silicone oil creaming to the top of the composition and thesilica sedimenting out. The comparative examples with SCC-C2 and SCC-C3started showing major coalescence and oiling within 30 minutes of beingmixed into the detergent composition.

We claim:
 1. A suds-controlling composition, which is liquid at 25° C.comprising(a) 100 parts by weight of a silicone antifoam which consistsessentially of (i) a liquid branched polyorganosiloxane material,wherein at least 50% of all units present have the general formula R₂--Si--O_(2/2), wherein R denotes a monovalent hydrocarbon group havingup to 24 carbon atoms and wherein at least 2 units have the generalstructure R--Si--O_(3/2) or Si--O_(4/2), any other units having thegeneral formula ##STR4## wherein a has a value of from 0 to 3 and R'denotes a group R or a hydrogen or hydroxyl group, and (ii) a finelydivided filler having its surface rendered hydrophobic, (b) from 33 to300 parts by weight of a polyorganosiloxane polyoxyalkylene copolymer,which is neither fully soluble in an aqueous surfactant solution norfully soluble in the liquid polyorganosiloxane (a) (i), and (c) 200 to400 parts by weight of a cyclic organopolysiloxane.
 2. Asuds-controlling composition according to claim 1, wherein at least 80%of all units of the liquid branched polyorganosiloxane material have theformula R₂ SiO_(2/2) and all other units are either units of the formulaRSiO_(3/2) or SiO_(4/2).
 3. A suds-controlling composition according toclaim 2, wherein at least 80% of all R groups of the liquid branchedpolyorganosiloxane material are methyl or phenyl groups.
 4. Asuds-controlling composition according to claim 3, wherein the averagediameter of the fillers ranges from 0.1 to 20 μ.
 5. A suds-controllingcomposition according to claim 4, wherein the silicone antifoamcomprises from 2 to 20% by weight of fillers.
 6. A suds-controllingcompsoition according to claim 5, wherein the silicone antifoam has aviscosity at 25° C. of from 3,000 to 35,000 mPa.s.
 7. A suds-controllingcomposition according to claim 1, wherein the polyorganosiloxanepolyoxyalkylene copolymer has the general formula ##STR5## wherein Rdenotes an alkyl or aryl group having up to 18 carbon atoms,A denotes adivalent alkylene unit having from 2 to 6 carbon atoms, optionallyinterrupted by an oxygen atom, B denotes a capping unit, Z denotes adivalent alkylene group having 2 to 8 carbon atoms, x, y, and c have avalue chosen thus that the copolymer is neither fully soluble in anaqueous surfactant solution, nor fully soluble in liquidpolyorganosiloxane material (a) (i).
 8. A suds-controlling compositionaccording to claim 7, wherein at least 80% of all the R groups of thepolyorganosiloxane polyoxyalkylene copolymer are methyl groups, Adenotes a C₂ or C₃ alkylene unit, z denotes a dimethylene group for themajority of Z groups present and B denotes a hydroxyl group or an acylgroup.
 9. A suds-controlling composition according to claim 8, whereinin the polyorganosiloxane polyoxyalkylene copolymers the value of x+y isin the range of from 80 to 350, y/x+y is from 0.05 to 0.08 and c is inthe range from 4 to
 40. 10. A suds-controlling composition according toclaim 9, wherein there is present at least 85 to 150 parts of copolymer(b) for every 100 parts of antifoam (a).
 11. An aqueous surfactantcomposition comprising(A) from 10 to 50 parts by weight of a nonionicsurfactant, (B) from 10 to 50 parts by weight of an anionic surfactant,(C) sufficient of a suds controlling composition which is liquid at 25°C. comprising(a) 100 parts by weight of a silicone antifoam whichconsists essentially of (i) a liquid branched polyorganosiloxanematerial, wherein at least 50% of all units present have the generalformula R₂ --Si--O_(2/2), wherein R denotes a monovalent hydrocarbongroup having up to 15 carbon atoms and wherein at least 2 units have thegeneral structure R--Si--O_(3/2) or Si--O_(4/2), any other units havingthe general formula ##STR6## wherein a has a value of from 0 to 3 and R'denotes a group R or a hydrogen or hydroxyl group, and (ii) a finelydivided filler having its surface rendered hydrophobic, and (b) from 33to 300 parts by weight of a polyorganosiloxane polyoxyalkylenecopolymer, which is neither fully soluble in the surfactant compositionnor fully soluble in the liquid polyorganosiloxane (a) (i), and (D) 200to 400 parts by weight of a cyclic organopolysiloxane to give a siliconeantifoam content of from 0.01 to 5% by weight based on the total weightof the composition.